Gage for determining curvature of saw-blade edges.



- N01 849,510. PATENTED APR. 9, 1907.

S. E. SMITH.

GAGE FOR DETERMINING GURVATURE OF SAW BLADE EDGES.

APPLIOATION FILED MAY 12, 1996.

1n: NORRIS Inns cm, WASHINOYDN. m c.

UNITED STATES PATENT QFFTCEO GAGE FOR DETERWHNING CURVATUFEE OF SAVKIBLADE EDGEEB.

Specification of Letters Patentv 'atentec. i-Apltu 9, 1907.

Application filed May 12,1906 Serial No. 316,486.

To (LZZ whom it 71mg; eon/eerie;

Be t known that I, SENECA EDWARD SMITH, a citizen of the United States of America, residing at the city oi Victoria, in the Province oi British Columbia, Canada, have invented a new and useful G Determining Curvature of saw-Biade items. 1

of which the following is I This invention relates an iauoroyed means for detecting" any i t' :n from a straight line in the back edge e1 a bandsaw,

and is designed to ailcrd a saw-sharpener l means of jut ging how to relieve the ((lQ bending stresses which are set up in a sawblade by the grinding of the teeth.

The operation of grinding the teeth 01' a band-saw stretches the length of that edge 01 the blade and renders the back edge hollow or concave, and this stress must be relieved in order that the saw may run evenly on its pulleys and that the strain of the work may be properly distributed over its cross-section. Such stresses are relieved by means of powerful compressing-rolls; but to enable the operator to judge where and to what extent to apply these rolls he must first ascertain with some degree of certainty what amount 01 curvature there is in the edge of the blade. This 1s usually determined by the application of a straight-edge or by application of the edge of the blade to a straight scribed hnc on the bench-plate; but such methods not only require close and tedious examination, but

are unsatisfactory, owing to the diiliculty of detecting slight deviations or of determining the amount oi suchwith reasonable precision.

I therefore provide a gage that will automatically indicate whether the edge of a blade is hollow or crowned, concave or convex, and to What extent, while a band-saw blade is being moved past it on the bench, and the device is designed to multiply the amount of deviation to the indicator of the gage, so as to render it visible at a g ance.

The appliance is fully described in the course of the following specification and illustrated in the drawings by which it is accompanied, in Which- Figure 1 is a plan showing the gage in use ig. 2, an enlarged cross-section on the line 2 2 in Fig. 1, and Fig. 3 a similar view on the line 3 3 in Fig. 1.

In the drawings, 2 represents the blade of a band-saw under observation, 3 being the bench to which the device is secured, and 4 the bench-plate.

Secured onthe bench about four feet apart I are steps against which the back edge oil the saw is applied, and these stops all'ord a base i between which deviations oi the cdgjgc of a l l l ht line between them are These steps n :iznply secur d in the b nch-p to and pre- 7 g l 'e the plane or it upper m l but as shown in the drawn l elsn tl members .5, each h l '-pro i=: rtin shank. G,

be arured to the wei a sr w and wing-nuts 7. the shank (i be ing furnished with an eion ted spttedaperture 8 to provide means for ad ustmcnt bar-ls l ward or forward to meet variations in the '1 width 01 the saw-blaue. Tl ou cl u (5.11 the member 5 enables the device to be used 11 on a double-cutting band-saw, as the length oi it will span the teeth, and, moreover, the length ollers a greater contact-surface to l withstand wear. I Secured to the bench 3 midway between I the stops 5 is the gage-box 10. This is a simple rectanguh'zr casting, hollow from the l under side and having screw-holes by which it may be secured to the bench. J Slidable cndwise through the ends of the l box is a stem 11, to the lront end of which is i secured an elongated cross bearing member 12, designed to bear on the edge of a. saw 4 under observation, and this inember 12 is i furnished with guide stems 13, shdable through the front end of the box. l The back end of the stem 11 is screwed and l provided outside the box with double nuts 1-1, by which adjustment may be made. A v pin 16 is secured in the gage-stem 11 and 1 projects upwardly through an elongated aperture 17 in the top of the box, and coiled on the stem 11 between the pin 16 and the f back inner end of the box is a spring 18, l which tends to press forward the stem and its attached parts. On the pin 16, where it n'ojeets'through the top or dial plate of the l ge-box 10, an indicati'ng-pointer 20 is pivotally connected,-which pointer is itself pivotally mounted at 21 in the top plate close to y the pin 16, so that any cndwise movement of i the stem 11 will be multiplied to the end of I the pointer in any desired ratio, the arc of movement on the plate being graduated each way from a zero-point corresponding to the position of the member 12 when its front face is in alincment with those of the members 5. i In the operation of the device the back edge of the saw-blade is pressed against the stops 5, and the spring on the stem 11 will press the member 12 against the blade midway between the two stops 5, and the pointer 20 will indicate whether the edge of the blade is straight, crowned, or hollow, and the amount of such crowning or hollo'wing, if there be any. If as drawn the teeth of the saw be allowed to project over the benchplate, the blade may by the application of the body of the operator be moved slowly past the gage, while the hands are free to mark the blade where it is required to be stretched.

Having now particularly described my invention, wnat 1 claim as new, and desire to be protected in by Letters Patent, is

1. In a device of the class described, the combination. with a bench or support, or" adjustable stops spaced a convenient distance apart offering an elongated bearing-surface to the edge of a saw, a gage member comvirtue of which the movement of the slidable member will be multiplied to the end of the pointer, and a spring to press the slidable member in contact with the edge of a blade on the support.

2. A device of the class described, comprising the combination with a bench or support for a saw-blade, stop members adjustably secured to said bench a convenient distance apart, against which the edge of the blade is adapted to rest, of a gage member secured to the support between the adjustable stops and comprising a casing, a blade-engagin member having a stem endwise slidable nin said casing, a po nter pivotally connected to said casing, and to said stem, and

means for normally pressing said saw-engaging member of the gage against the edge of the saw-blade, substantially as shown and described.

In testimony whereof I have signed my name to this specification in the presence of prising a casing, a stem slidable endwise in 1 two subscribing witnesses.

the support, and having means for engaging l the edge of the blade, a pointer pivotally connected to the stem and fulcrumed to said casing at a point adjacent the stem, said pointer and said stem having provisions in SENECA EDWARD SMITH.

Witnesses WM. DEHL, VIM. RITCHIE. 

